I like them, they add variety and make the round more fun. However, this post got me thinking about the idea that blind shots play better on links courses (or any course that is firm) than on typical soggy parkland courses. It's fun to hit a blind shot then get up to the top the hill and wonder how the hell your ball got where it is, whether this 3 feet from the hole or 50 yards right of where you thought.
Blind shots on courses where the ball rolls less are still interesting, but the element of surprise or suspense is lessened because the result is more predictable from where the shot was hit. Many people might think this is "unfair", but I think the added fun is worth the price of less predictability. I've only played a handful of links courses, but I imagine the blind shots being more fun when the roll out is greater.